Fix spelling error in the Statistics::R pod

--- a/lib/Statistics/R.pm
+++ b/lib/Statistics/R.pm
@@ -90,7 +90,7 @@
 
    my $out = $R->run( q`print( 1 + 2 )` );
 
-If you intend on runnning many R commands, it may be convenient to pass a list
+If you intend on running many R commands, it may be convenient to pass a list
 of commands or put multiple commands in an here-doc:
 
    # List of R commands: